Qubit class supports get item

.github/workflows/test-lock.yml

@@ -9,7 +9,7 @@ jobs:
     strategy:
       matrix:
         os: [ ubuntu-latest ]
-        python-version: [ "3.7", "3.8", "3.9", "3.10", "3.11" ]
+        python-version: [ "3.8", "3.9", "3.10", "3.11" ]
     runs-on: ${{ matrix.os }}
     steps:
       - name: Check out OQpy
@@ -23,7 +23,7 @@ jobs:
 
       - name: Install poetry
         run: |
-          make install-poetry
+          make install-poetry poetry_version=1.5.1
           poetry --version
           poetry config virtualenvs.in-project true
 

.github/workflows/test.yml

@@ -12,7 +12,7 @@ jobs:
     strategy:
       matrix:
         os: [ ubuntu-latest ]
-        python-version: [ "3.7", "3.8", "3.9", "3.10", "3.11" ]
+        python-version: [ "3.8", "3.9", "3.10", "3.11" ]
     runs-on: ${{ matrix.os }}
     steps:
       - name: Check out OQpy
@@ -79,7 +79,7 @@ jobs:
     strategy:
       matrix:
         os: [ ubuntu-latest ]
-        python-version: [ "3.7", "3.8", "3.9", "3.10", "3.11" ]
+        python-version: [ "3.8", "3.9", "3.10", "3.11" ]
     runs-on: ${{ matrix.os }}
     steps:
       - name: Check out OQpy
@@ -93,7 +93,7 @@ jobs:
 
       - name: Install poetry
         run: |
-          make install-poetry
+          make install-poetry poetry_version=1.5.1
           poetry --version
           poetry config virtualenvs.in-project true
 

Makefile

@@ -46,4 +46,4 @@ check-citation:
 .PHONY: install-poetry
 install-poetry:
 	command -v curl >/dev/null 2>&1 || { echo >&2 "please install curl and retry."; exit 1; }
-	curl -sSL https://install.python-poetry.org | python -
+	curl -sSL https://install.python-poetry.org | POETRY_VERSION=$(poetry_version) python -

oqpy/base.py

@@ -22,20 +22,23 @@
 from __future__ import annotations
 
 import math
-import sys
 from abc import ABC, abstractmethod
-from typing import TYPE_CHECKING, Any, Iterable, Optional, Sequence, Union
+from typing import (
+    TYPE_CHECKING,
+    Any,
+    Iterable,
+    Optional,
+    Protocol,
+    Sequence,
+    Union,
+    runtime_checkable,
+)
 
 import numpy as np
 from openpulse import ast
 
 from oqpy import classical_types
 
-if sys.version_info >= (3, 8):
-    from typing import Protocol, runtime_checkable
-else:
-    from typing_extensions import Protocol, runtime_checkable
-
 if TYPE_CHECKING:
     from oqpy import Program
 

oqpy/classical_types.py

@@ -62,7 +62,6 @@
     "ComplexVar",
     "DurationVar",
     "OQFunctionCall",
-    "OQIndexExpression",
     "StretchVar",
     "_ClassicalVar",
     "duration",
@@ -236,6 +235,25 @@ def __init__(self, *args: Any, size: int | None = None, **kwargs: Any):
             self.size = size
         super().__init__(*args, **kwargs, size=ast.IntegerLiteral(self.size) if self.size else None)
 
+    def _validate_getitem_index(self, index: AstConvertible) -> None:
+        """Validate the index and variable for `__getitem__`.
+
+        Args:
+            var (_SizedVar): Variable to apply `__getitem__`.
+            index (AstConvertible): Index for `__getitem__`.
+        """
+        if self.size is None:
+            raise TypeError(f"'{self.name}' is not subscriptable")
+
+        if isinstance(index, int):
+            if not 0 <= index < self.size:
+                raise IndexError("list index out of range.")
+        elif isinstance(index, OQPyExpression):
+            if not isinstance(index.type, (ast.IntType, ast.UintType)):
+                raise IndexError("The list index must be an integer.")
+        else:
+            raise IndexError("The list index must be an integer.")
+
 
 _SizedVarT = TypeVar("_SizedVarT", bound=_SizedVar)
 
@@ -274,7 +292,8 @@ class BitVar(_SizedVar):
     type_cls = ast.BitType
 
     def __getitem__(self, index: AstConvertible) -> OQIndexExpression:
-        return OQIndexExpression(collection=self, index=index)
+        self._validate_getitem_index(index)
+        return OQIndexExpression(collection=self, index=index, type_=self.type_cls())
 
 
 class ComplexVar(_ClassicalVar):
@@ -380,31 +399,16 @@ def __init__(
         )
 
     def __getitem__(self, index: AstConvertible) -> OQIndexExpression:
-        return OQIndexExpression(collection=self, index=index)
+        return OQIndexExpression(collection=self, index=index, type_=self.base_type().type_cls())
 
 
 class OQIndexExpression(OQPyExpression):
     """An oqpy expression corresponding to an index expression."""
 
-    def __init__(self, collection: AstConvertible, index: AstConvertible):
+    def __init__(self, collection: AstConvertible, index: AstConvertible, type_: ast.ClassicalType):
         self.collection = collection
         self.index = index
-
-        if isinstance(collection, ArrayVar):
-            self.type = collection.base_type().type_cls()
-
-        if isinstance(collection, _SizedVar):
-            if collection.size is None:
-                raise TypeError(f"'{collection.type_cls}' object is not subscriptable")
-
-            if isinstance(self.index, int):
-                if not 0 <= self.index < collection.size:
-                    raise IndexError("list index out of range.")
-            elif isinstance(self.index, OQPyExpression):
-                if not isinstance(self.index.type, (ast.IntType, ast.UintType)):
-                    raise IndexError("The list index must be an integer.")
-            else:
-                raise IndexError("The list index must be an integer.")
+        self.type = type_
 
     def to_ast(self, program: Program) -> ast.IndexExpression:
         """Converts this oqpy index expression into an ast node."""

oqpy/program.py

@@ -483,7 +483,7 @@ def gate(
         self, qubits: AstConvertible | Iterable[AstConvertible], name: str, *args: Any
     ) -> Program:
         """Apply a gate to a qubit or set of qubits."""
-        if isinstance(qubits, quantum_types.Qubit):
+        if isinstance(qubits, (quantum_types.Qubit, quantum_types.IndexedQubitArray)):
             qubits = [qubits]
         assert isinstance(qubits, Iterable)
         self._add_statement(
@@ -523,6 +523,14 @@ def pragma(self, command: str) -> Program:
         self._add_statement(ast.Pragma(command))
         return self
 
+    def include(self, path: str) -> Program:
+        """Add an include statement."""
+        if len(self.stack) != 1:
+            # cf. https://openqasm.com/language/comments.html#included-files
+            raise RuntimeError("Include statements must be global")
+        self._add_statement(ast.Include(path))
+        return self
+
     def _do_assignment(self, var: AstConvertible, op: str, value: AstConvertible) -> None:
         """Helper function for variable assignment operations."""
         if isinstance(var, classical_types.DurationVar):

oqpy/quantum_types.py

@@ -30,7 +30,7 @@
     from oqpy.program import Program
 
 
-__all__ = ["Qubit", "QubitArray", "defcal", "gate", "PhysicalQubits", "Cal"]
+__all__ = ["Qubit", "defcal", "gate", "PhysicalQubits", "Cal"]
 
 
 class Qubit(Var):
@@ -39,11 +39,13 @@ class Qubit(Var):
     def __init__(
         self,
         name: str,
+        size: Optional[int] = None,
         needs_declaration: bool = True,
         annotations: Sequence[str | tuple[str, str]] = (),
     ):
         super().__init__(name, needs_declaration=needs_declaration)
         self.name = name
+        self.size = size
         self.annotations = annotations
 
     def to_ast(self, prog: Program) -> ast.Expression:
@@ -53,10 +55,18 @@ def to_ast(self, prog: Program) -> ast.Expression:
 
     def make_declaration_statement(self, program: Program) -> ast.Statement:
         """Make an ast statement that declares the OQpy variable."""
-        decl = ast.QubitDeclaration(ast.Identifier(self.name), size=None)
+        decl = ast.QubitDeclaration(
+            ast.Identifier(self.name),
+            size=ast.IntegerLiteral(self.size) if self.size else self.size,
+        )
         decl.annotations = make_annotations(self.annotations)
         return decl
 
+    def __getitem__(self, index: AstConvertible) -> IndexedQubitArray:
+        if self.size is None:
+            raise TypeError(f"'{self.name}' is not subscriptable")
+        return IndexedQubitArray(collection=self, index=index)
+
 
 class PhysicalQubits:
     """Provides a means of accessing qubit variables corresponding to physical qubits.
@@ -68,9 +78,18 @@ def __class_getitem__(cls, item: int) -> Qubit:
         return Qubit(f"${item}", needs_declaration=False)
 
 
-# Todo (#51): support QubitArray
-class QubitArray:
-    """Represents an array of qubits."""
+class IndexedQubitArray:
+    """Represents an indexed qubit array."""
+
+    def __init__(self, collection: Qubit, index: AstConvertible):
+        self.collection = collection
+        self.index = index
+
+    def to_ast(self, program: Program) -> ast.IndexExpression:
+        """Converts this indexed qubit array into an ast node."""
+        return ast.IndexExpression(
+            collection=to_ast(program, self.collection), index=[to_ast(program, self.index)]
+        )
 
 
 @contextlib.contextmanager